// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holders nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// THE POSSIBILITY OF SUCH DAMAGE.
package cn.taketoday.context.asm;

/**
 * A {@link FieldVisitor} that generates a corresponding 'field_info' structure,
 * as defined in the Java Virtual Machine Specification (JVMS).
 *
 * @author Eric Bruneton
 * @see <a href=
 * "https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.5">JVMS
 * 4.5</a>
 */
final class FieldWriter extends FieldVisitor {

  /** Where the constants used in this FieldWriter must be stored. */
  private final SymbolTable symbolTable;

  // Note: fields are ordered as in the field_info structure, and those related to
  // attributes are
  // ordered as in Section 4.7 of the JVMS.

  /**
   * The access_flags field of the field_info JVMS structure. This field can
   * contain ASM specific access flags, such as {@link Opcodes#ACC_DEPRECATED},
   * which are removed when generating the ClassFile structure.
   */
  private final int accessFlags;

  /** The name_index field of the field_info JVMS structure. */
  private final int nameIndex;

  /** The descriptor_index field of the field_info JVMS structure. */
  private final int descriptorIndex;

  /**
   * The signature_index field of the Signature attribute of this field_info, or 0
   * if there is no Signature attribute.
   */
  private int signatureIndex;

  /**
   * The constantvalue_index field of the ConstantValue attribute of this
   * field_info, or 0 if there is no ConstantValue attribute.
   */
  private int constantValueIndex;

  /**
   * The last runtime visible annotation of this field. The previous ones can be
   * accessed with the {@link AnnotationWriter#previousAnnotation} field. May be
   * {@literal null}.
   */
  private AnnotationWriter lastRuntimeVisibleAnnotation;

  /**
   * The last runtime invisible annotation of this field. The previous ones can be
   * accessed with the {@link AnnotationWriter#previousAnnotation} field. May be
   * {@literal null}.
   */
  private AnnotationWriter lastRuntimeInvisibleAnnotation;

  /**
   * The last runtime visible type annotation of this field. The previous ones can
   * be accessed with the {@link AnnotationWriter#previousAnnotation} field. May
   * be {@literal null}.
   */
  private AnnotationWriter lastRuntimeVisibleTypeAnnotation;

  /**
   * The last runtime invisible type annotation of this field. The previous ones
   * can be accessed with the {@link AnnotationWriter#previousAnnotation} field.
   * May be {@literal null}.
   */
  private AnnotationWriter lastRuntimeInvisibleTypeAnnotation;

  /**
   * The first non standard attribute of this field. The next ones can be accessed
   * with the {@link Attribute#nextAttribute} field. May be {@literal null}.
   *
   * <p>
   * <b>WARNING</b>: this list stores the attributes in the <i>reverse</i> order
   * of their visit. firstAttribute is actually the last attribute visited in
   * {@link #visitAttribute}. The {@link #putFieldInfo} method writes the
   * attributes in the order defined by this list, i.e. in the reverse order
   * specified by the user.
   */
  private Attribute firstAttribute;

  // -----------------------------------------------------------------------------------------------
  // Constructor
  // -----------------------------------------------------------------------------------------------

  /**
   * Constructs a new {@link FieldWriter}.
   *
   * @param symbolTable
   *         where the constants used in this FieldWriter must be stored.
   * @param access
   *         the field's access flags (see {@link Opcodes}).
   * @param name
   *         the field's name.
   * @param descriptor
   *         the field's descriptor (see {@link Type}).
   * @param signature
   *         the field's signature. May be {@literal null}.
   * @param constantValue
   *         the field's constant value. May be {@literal null}.
   */
  FieldWriter(final SymbolTable symbolTable, final int access, final String name, final String descriptor,
              final String signature, final Object constantValue) //
  {
    this.symbolTable = symbolTable;
    this.accessFlags = access;
    this.nameIndex = symbolTable.addConstantUtf8(name);
    this.descriptorIndex = symbolTable.addConstantUtf8(descriptor);
    if (signature != null) {
      this.signatureIndex = symbolTable.addConstantUtf8(signature);
    }
    if (constantValue != null) {
      this.constantValueIndex = symbolTable.addConstant(constantValue).index;
    }
  }

  // -----------------------------------------------------------------------------------------------
  // Implementation of the FieldVisitor abstract class
  // -----------------------------------------------------------------------------------------------

  @Override
  public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) {
    // Create a ByteVector to hold an 'annotation' JVMS structure.
    // See
    // https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.16.
    ByteVector annotation = new ByteVector();
    // Write type_index and reserve space for num_element_value_pairs.
    annotation.putShort(symbolTable.addConstantUtf8(descriptor)).putShort(0);
    if (visible) {
      return lastRuntimeVisibleAnnotation
              = new AnnotationWriter(symbolTable,
                                     annotation,
                                     lastRuntimeVisibleAnnotation);
    }
    else {
      return lastRuntimeInvisibleAnnotation
              = new AnnotationWriter(symbolTable,
                                     annotation,
                                     lastRuntimeInvisibleAnnotation);
    }
  }

  @Override
  public AnnotationVisitor visitTypeAnnotation(final int typeRef, final TypePath typePath, final String descriptor,
                                               final boolean visible) {
    // Create a ByteVector to hold a 'type_annotation' JVMS structure.
    // See
    // https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.20.
    ByteVector typeAnnotation = new ByteVector();
    // Write target_type, target_info, and target_path.
    TypeReference.putTarget(typeRef, typeAnnotation);
    TypePath.put(typePath, typeAnnotation);
    // Write type_index and reserve space for num_element_value_pairs.
    typeAnnotation.putShort(symbolTable.addConstantUtf8(descriptor)).putShort(0);
    if (visible) {
      return lastRuntimeVisibleTypeAnnotation
              = new AnnotationWriter(symbolTable,
                                     typeAnnotation,
                                     lastRuntimeVisibleTypeAnnotation);
    }
    else {
      return lastRuntimeInvisibleTypeAnnotation
              = new AnnotationWriter(symbolTable,
                                     typeAnnotation,
                                     lastRuntimeInvisibleTypeAnnotation);
    }
  }

  @Override
  public void visitAttribute(final Attribute attribute) {
    // Store the attributes in the <i>reverse</i> order of their visit by this
    // method.
    attribute.nextAttribute = firstAttribute;
    firstAttribute = attribute;
  }

  @Override
  public void visitEnd() {
    // Nothing to do.
  }

  // -----------------------------------------------------------------------------------------------
  // Utility methods
  // -----------------------------------------------------------------------------------------------

  /**
   * Returns the size of the field_info JVMS structure generated by this
   * FieldWriter. Also adds the names of the attributes of this field in the
   * constant pool.
   *
   * @return the size in bytes of the field_info JVMS structure.
   */
  int computeFieldInfoSize() {
    // The access_flags, name_index, descriptor_index and attributes_count fields
    // use 8 bytes.
    int size = 8;
    // For ease of reference, we use here the same attribute order as in Section 4.7
    // of the JVMS.
    if (constantValueIndex != 0) {
      // ConstantValue attributes always use 8 bytes.
      symbolTable.addConstantUtf8(Constants.CONSTANT_VALUE);
      size += 8;
    }
    // Before Java 1.5, synthetic fields are represented with a Synthetic attribute.
    if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && symbolTable.getMajorVersion() < Opcodes.V1_5) {
      // Synthetic attributes always use 6 bytes.
      symbolTable.addConstantUtf8(Constants.SYNTHETIC);
      size += 6;
    }
    if (signatureIndex != 0) {
      // Signature attributes always use 8 bytes.
      symbolTable.addConstantUtf8(Constants.SIGNATURE);
      size += 8;
    }
    // ACC_DEPRECATED is ASM specific, the ClassFile format uses a Deprecated
    // attribute instead.
    if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
      // Deprecated attributes always use 6 bytes.
      symbolTable.addConstantUtf8(Constants.DEPRECATED);
      size += 6;
    }
    if (lastRuntimeVisibleAnnotation != null) {
      size += lastRuntimeVisibleAnnotation.computeAnnotationsSize(Constants.RUNTIME_VISIBLE_ANNOTATIONS);
    }
    if (lastRuntimeInvisibleAnnotation != null) {
      size += lastRuntimeInvisibleAnnotation.computeAnnotationsSize(Constants.RUNTIME_INVISIBLE_ANNOTATIONS);
    }
    if (lastRuntimeVisibleTypeAnnotation != null) {
      size += lastRuntimeVisibleTypeAnnotation.computeAnnotationsSize(Constants.RUNTIME_VISIBLE_TYPE_ANNOTATIONS);
    }
    if (lastRuntimeInvisibleTypeAnnotation != null) {
      size += lastRuntimeInvisibleTypeAnnotation.computeAnnotationsSize(Constants.RUNTIME_INVISIBLE_TYPE_ANNOTATIONS);
    }
    if (firstAttribute != null) {
      size += firstAttribute.computeAttributesSize(symbolTable);
    }
    return size;
  }

  /**
   * Puts the content of the field_info JVMS structure generated by this
   * FieldWriter into the given ByteVector.
   *
   * @param output
   *         where the field_info structure must be put.
   */
  void putFieldInfo(final ByteVector output) {
    boolean useSyntheticAttribute = symbolTable.getMajorVersion() < Opcodes.V1_5;
    // Put the access_flags, name_index and descriptor_index fields.
    int mask = useSyntheticAttribute ? Opcodes.ACC_SYNTHETIC : 0;
    output.putShort(accessFlags & ~mask).putShort(nameIndex).putShort(descriptorIndex);
    // Compute and put the attributes_count field.
    // For ease of reference, we use here the same attribute order as in Section 4.7
    // of the JVMS.
    int attributesCount = 0;
    if (constantValueIndex != 0) {
      ++attributesCount;
    }
    if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && useSyntheticAttribute) {
      ++attributesCount;
    }
    if (signatureIndex != 0) {
      ++attributesCount;
    }
    if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
      ++attributesCount;
    }
    if (lastRuntimeVisibleAnnotation != null) {
      ++attributesCount;
    }
    if (lastRuntimeInvisibleAnnotation != null) {
      ++attributesCount;
    }
    if (lastRuntimeVisibleTypeAnnotation != null) {
      ++attributesCount;
    }
    if (lastRuntimeInvisibleTypeAnnotation != null) {
      ++attributesCount;
    }
    if (firstAttribute != null) {
      attributesCount += firstAttribute.getAttributeCount();
    }
    output.putShort(attributesCount);
    // Put the field_info attributes.
    // For ease of reference, we use here the same attribute order as in Section 4.7
    // of the JVMS.
    if (constantValueIndex != 0) {
      output.putShort(symbolTable.addConstantUtf8(Constants.CONSTANT_VALUE)).putInt(2).putShort(constantValueIndex);
    }
    if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && useSyntheticAttribute) {
      output.putShort(symbolTable.addConstantUtf8(Constants.SYNTHETIC)).putInt(0);
    }
    if (signatureIndex != 0) {
      output.putShort(symbolTable.addConstantUtf8(Constants.SIGNATURE)).putInt(2).putShort(signatureIndex);
    }
    if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
      output.putShort(symbolTable.addConstantUtf8(Constants.DEPRECATED)).putInt(0);
    }
    if (lastRuntimeVisibleAnnotation != null) {
      lastRuntimeVisibleAnnotation.putAnnotations(symbolTable.addConstantUtf8(Constants.RUNTIME_VISIBLE_ANNOTATIONS), output);
    }
    if (lastRuntimeInvisibleAnnotation != null) {
      lastRuntimeInvisibleAnnotation.putAnnotations(symbolTable.addConstantUtf8(Constants.RUNTIME_INVISIBLE_ANNOTATIONS), output);
    }
    if (lastRuntimeVisibleTypeAnnotation != null) {
      lastRuntimeVisibleTypeAnnotation.putAnnotations(symbolTable.addConstantUtf8(Constants.RUNTIME_VISIBLE_TYPE_ANNOTATIONS),
                                                      output);
    }
    if (lastRuntimeInvisibleTypeAnnotation != null) {
      lastRuntimeInvisibleTypeAnnotation.putAnnotations(symbolTable.addConstantUtf8(Constants.RUNTIME_INVISIBLE_TYPE_ANNOTATIONS),
                                                        output);
    }
    if (firstAttribute != null) {
      firstAttribute.putAttributes(symbolTable, output);
    }
  }

  /**
   * Collects the attributes of this field into the given set of attribute
   * prototypes.
   *
   * @param attributePrototypes
   *         a set of attribute prototypes.
   */
  final void collectAttributePrototypes(final Attribute.Set attributePrototypes) {
    attributePrototypes.addAttributes(firstAttribute);
  }
}
